1. Field of the Invention
The present invention relates generally to direct current (DC) electric motors and, more particularly, to DC electric motors with motor-cooling features.
2. Description of the Prior Art
It is well known that DC electric motors give off heat when they operate. With many motors, ambient air is sufficient for cooling the motors. Even a fan blowing ambient air may also provide sufficient cooling. However, for a DC electric motor that performs relatively large amounts of work and generates more heat than can be sufficiently cooled merely by air, it would be desirable if a DC electric motor were provided with a liquid cooling system.
Generally, a conventional DC electric motor has a simple stator, an armature that includes a pair of armature poles wherein one armature pole has a right-handed winding, and the other armature pole has a left-handed winding. Also, such a conventional DC electric motor includes a commutator that has two commutator contacts. Also, a conventional DC electric motor includes sliding brushes.
With the present invention, a number of improvements over a conventional DC electric motor are contemplated. For example, it would be desirable to provide a novel DC electric motor which provides a stator comprised of a plurality of stator magnet modules. It is contemplated that multiple stator magnet modules can provide maximum torque.
With the present invention, instead of employing an armature that has only two armature pole portions, it would be desirable to provide a DC electric motor that has an armature that includes additional armature pole portions. The use of multiple armature pole portions will permit the maximizing of the efficiency of available electric current.
With the present invention, instead of having opposite armature pole portions that have opposite winding configurations, such as right-handed winding and left-handed winding, it has been discovered beneficial to have opposite armature pole portions to have the same winding configurations. That is, both opposite armature pole portions can have either right-handed windings or left-handed windings.
With the present invention, instead of using conventional sliding brushes, the invention employs roller brushes. Roller brushes last longer than sliding brushes.
In addition, instead of employing a conventional bearing for the armature, the present invention provides a tunnel bearing assembly which puts the bearings close to the armature for better stability and load supporting.
Conventionally, brushes are retained in fixed positions with respect to the commutator contacts. That is, even with different motor speeds and different loads, the relative positions between the commutator contacts and the brushes do not change. In this respect, it would be desirable if a brush advance/retard mechanism were provided. Such a brush advance/retard mechanism would allow for maximum performance at different motor speeds and loads.
Thus, while the foregoing body of prior art indicates it to be well known to use DC electric motors, the above discussion indicates that the prior art does not teach or suggest a DC motor apparatus which has the following combination of desirable features: (1) is provided with a liquid cooling system; (2) provides a stator comprised of a plurality of stator magnet modules; (3) has an armature that includes additional armature pole portions; (4) has opposite armature pole portions having the same winding configurations; (5) employs roller brushes; (6) provides a tunnel bearing assembly; and (7) provides a brush advance/retard mechanism. The foregoing desired characteristics are provided by the unique liquid cooled DC motor apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.